Heater



H. B. SHARP o ts,- 1937'.

HEATER- Filed NOV. 24;,1934 3 Sheets-Sheet 1 INVENTOR Howard 5.5/20.

ATTORNEY Oct. 5, 1937.

H. B. SHARP HEATER Filed Nov. 24, 1934 a Sheets-Sheet? Till/villi!all/4721A; Ell/ll N 4 VD Q 6 INVENTOR Howard B. 5/10, rp

ATTORNEY Oct. 5, 1937; H. B. SHARP 4,

' HEATER Filed Nov. 24, 1934 3 Sheets-Sheet 3 INVENTOR ATTORNEY PatentedOct. 5, 1937 UNITED STATES HEATER Howard B. Sharp, Independence, Mo.,assignor to Standard Oil Company, Chicago, Ill., a corporation ofIndiana Application November 24, 1934, Serial No. 754,642

6 Claims.

This invention relates to improvements in heaters, and more particularlyheaters such as tube heaters or pipe stills commonly employed in thepetroleum refining industry for heating or 5 cracking petroleumproducts.

It is customary, in the construction of heaters of the type described,to build a heater with a combustion chamber and one or morecommunicating convection chambers, which are separated from each otherby a vertical wall or bridge wall, which serves as a screen againstradiant heat but permits the passage of hot gases or hot products ofcombustion. For the most part, such heaters are built with a singlecombustion chamber and a single convection chamber. The fuel which is tobe burned in the combustion chamber is usually introduced throughburners in the wall oppositev the bridge Wallthis wall being generallytermed the front wall, or the burners may also be placed in the sidewalls. The hot gases from the combustion of the fuel, thus introduced,flow inwardly and upwardly, thence over the bridge wall and thencedownwardly through the convection chamber to a point adjacent the bottomthereof, whence they are discharged through one or more flues and thencepermitted to pass to the stack. The oil to be heated is passed throughtubes which are generally disposed adjacent the roof, floor, or Walls ofthe combustion chamber and also disposed in banks of tubes in theconvection chamber, the tubes being usually horizontal and parallel tothe bridge wall.

In the operation of such heaters it is frequently noted that thetemperature of the gases at one side of the combustion chamber is verymuch higher than that at the opposite side and the zone of greatest heatintensity, sometimes called the hot spot, is disposed to shift from sideto side in the combustion chamber. It is believed that this shifting ofthe hot spot in the combustion chamber is due to one or more of severalfactors, which include uneven firing, the effect of Wind on the exteriorwall of the heater which causes air to leak through the intersticesofthe brickwork, as well as to the stack effect, or draft. Actualobservation on operating heaters indicates differences in temperaturesof as much as 20% when measured along opposite walls of the combustionchamber..

Once the temperature in the combustion chamber becomes unbalanced it hasbeen found to be extremely difficult to shift the zone of increasedtemperature to the central region of 3 the chamber, where it properlybelongs. Moreover, where the unbalanced condition exists in the heaternaturally the tubes adjacent one wall of the heater will tend to becomeoverheated, While the tubes adjacent the opposite wall will beunderheated. This results in improper heat- 5 ing, incompletecombustion, and inefiicient operation of the heater.

One of the objects of my invention is to provide means for controllingthe location of the hot spot and for controlling the flow of hot gasthrough the combustion chamber and thence through the convection chamberso as to avoid overheating of the tubes and to cause uniform andeconomical operation of the heater at all times and under allconditions.

Another object of my invention is to provide an improved heater in whichthe proper temperature balance within the combustion chamber may bemaintained and controlled without the necessity of continuallymanipulating and readjusting the burners used in firing the heater.

Attempts. have been made to preserve the heat distribution in thecombustion section of a heater by controlling the distribution of gasesflowing from the convection section to the stack by means of dampers inseveral flue openings adjacent the bottom of the convection chamber.Actual experience in operating heaters equipped with a plurality of flueoutlets has shown that while the operation of such heater is animprovement over the operation of heaters equipped with but a singleflue connection, nevertheless unbalanced temperature conditions and ashifting of the hot spot were experienced.

I have found that by subdividing the convection chamber into a pluralityof zones, preferably by means of vertical walls disposed at right anglesto the bridge wall and by providing each of these several zones with aseparate flue opening equipped with a valve or damper, the temperaturebalance in the combustion chamber may be maintained very readily and thehot spot may be shifted at will.

My invention is illustrated in the following drawings which form a partof this specification and in which like elements are represented byidentical reference numerals:

Figure 1 is a diagrammatic illustration of my improved heater, thedrawing being in perspective with parts thereof being broken away.

Figure 2 is a diagrammatic plan View.

Figure 3 is a simplified plan view showing the gas flow under normalconditions in a heater of the prior art type.

Figure 4 is a simplified plan View of a prior art heater showing theunbalancing of the gas flow which results in such heater without themanipulation of any of the dampers.

Figure 5 is a simplified plan view of a prior art heater showing the gasflow which results when one of. the dampers in said heater is operatedto shut off a fiue.

Figure 6 is a simplified plan View of my heater showing the gas flowwhich results under the same conditions which produce the unbalancing,

as represented in Figures 4 and 5 of the prior art,

heater.

Figure 7 is a shadow drawing in perspective of the prior art heater ofFigure 5.

Figure 8 is a detailed sectional view showing a fragmentary elevation ofone of the convection section partitions.

Figure 9 is a sectional View taken along the line 99 of Figure 8.

Figure 10 is another sectional view taken along the line !E|l0'of Figure8.

Figure 11 is a perspective view of a modified type of convection sectionpartitions.

Figure 12 is a sectional View taken along the line I2-l2 of Figure 11,and,

Figure 13 is another sectional view taken along the line i3l3 of Figure11.

- Referring to Figure 1, I have illustrated therein diagrammatically aconventional type of heater having side walls BAE, front wall AEN, sidewall NGI, and roof ABC, these walls being partly broken away and beingthe side wall, front wall, and roof, respectively of the combustionchamber; the floor of the combustion chamber is a surface EFGN. Thebridge wall is represented by the plane HFGI; The floor of theconvection chamber is represented by the plane JKML and the verticalpartitions which divide the convection chamber into zones arerepresented by thev planes POQR and TSUV respectively. The rear wall ofthe convection chamber is represented by the plane BCLJ and this wall isprovided'with' a plurality of orifices, one in each zone, and

numbered respectively I, 2,, and 3, the orifices being providedrespectively with dampers 4, 5, and 6. r

, On referring to Figure 2, which is a plan View of my heater, therewill be'found the front wall 8 and side walls 9 and [0 of the combustionchamber. The bridge wall l5 serves as the rear wall of the combustionchamber. Fuel nozzles l l introduce 'fuel for the purpose of combustionthrough the front wall 8. Oil-containing tubes l2, l3, and i4are'disposed adjacent the side wall 9, bridge wall l5, and side wall Inrespectively. The convection chamber is provided with side walls I! andI8 and vertical partitions l9 and 20, through which convection tubes I5are disposed, generally parallel to the bridge wall, having axes whichare horizontal. .At the lower part of the rear wall of the convectionchamber are flue connections l, 2, and 3, being provided with dampers 4,5, and 6 respectively, the flue The diagrammatic showing of Figure 7 issimilar to that of Figure 1, except that the heater is e that of theprior art type and does not include the vertical partitions which areshown in Figure l; the elements which are common to Figures 1 and 2 aregiven identical reference numerals.

In Figures 8, 9, and 10 I show'one type of construction of the verticalpartitions which are employed to separate the convection chamber intozones. In this type of construction the partitions are formed ofcorrugated elements 3| and 32, constructed with a plurality of. ports IEto per- .mit the partition-to be pierced by the convection tubes 6. Theassembled partition is maintained in vertical alignment by providing thebridge wall l5 and the opposite wall of the combustion chamber withrecesses 33 and the upper edge of the partition is assembled by boltingtogether channels 30, this providing a fairly rigid type of constructionwhich, at the same time, permits expansion of the elements of thepartition and permits it .to accommodate the convection tubes It, evenunder the stress of great heat. In Figures ll, 12, and 13 I haveillustrated a modified type of partition wall in which the partition isconstructed of a single plate which is ierced to permit the'insertio'nof the convection tubes l6. Split'rings' ll are disposed around eachtube and on opposite sides of the partition 40 the end of the partitionmay be guided in recesses 43 provided in the bridge Wall and the rearwall of the convection chamber. The split rings are preferably of heatresistant alloy and of sufficient size to' overlap the orifices in theplate 40 so as to establish a iairly gas-tight seal between the adjacentzones of the convection section, and so constructed'as to permit therings to embrace the tubes and at the same time to permit the rings toexpand, when the tubes expand, under heating; 7

- In operating my improved heater the position of the convection chamberis controlled by regulating the efiective area of one or more of theorifices l, 2, and 3, by means'of the respective dampers. Thisregulation may be illustrated by referring to Figures 3 to 6 inclusiveof the accompanying drawings. In Figure 3, which shows the prior arttype of construction without the items of my invention, under'perfectoperating conditions, the hot spot, which is represented by the oval inthe combustion chamber, is adjacent the center of the combustion sectionand slightly nearer the bridge wall. The hot gases fiowover the bridgewall in substantially uniform volume at all points, and thence flow downthrough the convection chamber. in substantially uniform volume andsubstantially equal amounts of hot gases will be discharged through theexit orifice at any given time. If however, the heater should besubjected to wind which approaches the heater from the directionadjacent the side wall 9, as shown in Figure 4, cooled air willpenetrate the interstices between the brickwork of side wall 9, the hotspot will be shifted toward side wall IE], and because of the greaterdensity of the cooler air adjacent side wall 9 more hot gases will flowover the bridge wall on the side toward side wall ID. This will tend toincrease the volume of hot gases discharged through orifice 3 of theconvection chamber and will diminish the volume of gas discharged toorifice I. i

If, in the prior art type of heater, it is attempted to rectify thiscondition of unbalance by closing oh the orifice 3by closing damper 6and completely opening orifice I by opening damper 4, it is found that'the hot spot is not shifted in the combustion chamber and the sametendency to accumulate a greater volume of hot gases adjacent side wallI0 is experienced, both in the combustion chamber and after the gasesflow over the bridge wall l5. This condition of unbalance continues, asillustrated by the arrows on Figure 7, until the gases have traverseddownwardly through most of the convection chamber and it is only towardthe low part of the convection chamber that the gases are drawn to theopen orifices because of the stack effect or draft created by the stack.

Under the same conditions of wind adjacent the side wall 9, with myinvention as illustrated in Figure 6 where orifice 3 is shut oiT byclosing damper 6 and orifice l is opened by fully opening damper 4 thereis no passage for the hot gases in the zone of the convection chamberadjacent the side wall 10. The hot gases in the combustion chamber,therefore, must pass over the bridge wall at points adjacent the twoopen zones controlled by orifices I and 2. More hot gases are thereforethrown adjacent side wall 9 and the hot spot is automatically shiftedback to its central position in the combustion chamber. Under thesecircumstances the tubes containing the oil to be heated in thecombustion chamber are uniformly heated and a balanced operation ismaintained in the combustion chamber.

My invention overcomes a serious problem in maintaining the properbalance in the combustion chamber of a heater, which may be illustratedby the following data indicating the various conditions of temperatureexisting in a heater provided with 3 outlet orifices from the convectionchamber, but not provided with the partitions which my inventioncontemplates. The temperatures given were taken at the center of theside walls which correspond to walls 9 and ID of the With theinstallation of partitions to divide the convection chamber and thezones, as contemplated by my invention, it is possible to maintain thetemperatures on opposite side walls of the combustion chamberapproximately the same at all times. I may also make the operation ofthe control dampers automatic in response to temperatures measured bythermocouples or other heat recording instruments placed on oppositesides of the combustion section. An increase in temperature on one sideof the chamber will automatically result in closing the damper on thatside a sufficient amount to compensate for the increase and even out thetemperature again.

Since many different embodiments of this invention, apparently differingwidely, may be made without departing from the spirit thereof, it is tobe understood that I do not limit myself to the foregoing descriptionexcept as indicated in the following claims:

I claim:

1. The method of controlling the position of the center of heatintensity and the direction of fiow of hot gases in the combustionsection of a heater, wherein the convection section has means dividingit into a plurality of vertical compartments having fluid heating tubespassing therethrough, said means comprising at least one verticalpartition wall extending from the bridge wall in a direction parallel tothe general direction of hot gas flow in the combustion section, eachcompartment being in open communication at its top with the combustionsection and otherwise closed except for individual damper means in eachcompartment, said method comprising controlling the relative quantity ofgas passing through each compartment of the convection section byregulating said individual damper means whereby to control the lateralshift of the center of heat concentration Within said combustion sectionin the direction corresponding to the compartment through which thegreater proportion of hot gases are caused to flow.

2. The method of operating a tubular type oil heater having a combustionsection separated from a convection section by a bridge wall andprovided with oil heating tubes therein, a plurality of verticalpartitions within said convection section extending from said bridgewall parallel to the general direction of hot gas flow in the combustionsection, thus defining a plurality of chambers in open communication attheir tops with the combustion section and otherwise closed except forindividual adjustable outlet means;

said method comprising controlling the indi-' vidual outlet means of therespective chambers to cause a larger proportion of the total gas flowto pass through one chamber than through another, thus causing lateralshift of the center of heat intensity in the combustion section to takeplace in the direction corresponding to the chamber through which thegreater portion of the gases are passed, whereby to control the heatingeffect and the direction of flow of hot gases in the combustion sectionto provide unchanging heating conditions in the combustion section..

3. In a tubular type heater, means defining an enclosed heater chamber,comprising a floor, a surrounding wall and roof; a bridge wall disposedtransversely of the general direction of flow of gases through saidheater and extending from said floor to a point below said roof, wherebyto divide said chamber into a combustion section and a convectionsection in communication with each other above said bridge wall, oilheating tubes arranged in banks within said combustion section and saidconvection section, means for effecting combustion within saidcombustion section, said convection section being characterized by theprovision of at least one vertical partition wall extending from saidfloor to a point below said roof, said partition wall extending fromsaid bridge wall to said surrounding wall and parallel to the generaldirection of hot gas flow in the combustion section, whereby to dividesaid convection section into at least two parallel verticalcompartments, said compartments being effective to divide said gas flowfrom said combustion section into two individual streams parallel toeach other along a line transverse to said general direction of hot gasflow in said combustion section, and individual damper means in each ofsaid compartments for controlling the relative quantity of gas flowthrough each of said compartments, whereby to cause the lateral shiftingof the center of heat intensity in said combustion section in thedirection of that compartment having the larger quantity of gas flowtherethrough.

a. In a tubular type heater,v means defining an enclosed heating chambercomprising a floor, a; surrounding wall, a roof, a bridge wall disposedtransversely of the general direction of flow of,

hot gases through said heater and extending from said floor to a pointbelow said roof whereby to divide said chamber into a combustionsectionand a convection section in communication with each other above saidbridge wall, oil heating tubes arranged in banks within said combustionsection and said convection section, said convection section beingcharacterized by the provision of a pluralityof vertical partition wallsextending from said'floor to a point below said roof, said: bank oftubesin said convection section being disposed transversely of saidgeneral direction of flow of hot gases through said heater, saidpartition walls extendingfrom said bridge wall to said surrounding walland having said convection tubes passing therethrough, whereby saidconvection section is divided into a plurality of substantiallycoextensive parallel vertical compartments effective to divide said gasflow from said combustion section into a plurality of individual streamsparallel to each other along a line transverse to said general directionof hot gas flow in said combustion section, and individual damper meansin each of said compartments for controlling the relative proportion ofgases fiow' ing through each compartment whereby to cause a lateralshifting of the center of heat intensity in said combustion section inaccordance with said relative proportioning of said hot gas flow.

5. In a tubular type heater, means defining an enclosed heating chambercomprising a floor, a surrounding wall, a roof, a bridge wall disposedtransversely to the gen ral directionof flow of hot gases through saidheater and extending from said floor to a point below said roof, whereby" to divide said chamber into a combustion section and a convectionsection in communica- 7 tion with each' other above said bridge wall,oil

heating tubes arranged in banks within said combustion section and saidconvection section, said convection :section ,being characterized by theprovision of a plurality of partition walls-extending from said floor toa point below said roof; said partition wallsextending from said bridgewall to said surrounding'wall parallel to the general direction of hotgas flow in the comindividual streams parallel to each other along a 7line transverse to the said general direction of hot gas flow in saidcombustion section, saidindividual' damper means being eiTective tocontrol the relative proportion of gas flow through each compartmentwhereby to cause a lateral shift of the center of heat intensity in saidcombustion section in accordance with said relative proportioning ofsaid hot gas flow.

6. In a tubular type heater, means defining an enclosed heating chambercomprising a floor, a

surrounding wall, roof, a bridge wall disposed transversely of saidheater and extending from said floor to a point below said roof, wherebyto divide said chamber into a combustion section and a convectionsection in communication with each other above said bridge wall, meansfor efiecting combustion within said combustion section, said convectionsection being characterized by the provision of a plurality of partitionwalls, said partition walls extending from said floor to a point belowsaid roof and from said bridge wall substantially perpendiculartherewith and connecting with said surrounding wall whereby to dividesaid convection section into a plurality of parallel verticalcompartments in open communication at their tops with said combustionsection and otherwise closed except for individual damper means in eachcompartment, said compartments being effective to divide said gas flowfrom said combustion section into a plurality of individual streamsparallel to each other along a line transverse to said general directionof hot gas flow in said combustion section, said individual damper meansbeing operable to control the relative quantity of gases flowing througheach

